Ok so this problem just started but when I’m at about 55mph the rpms are usually 1800 but then they drop to about 1400 an jump right back in a spot second, no idea what’s going on 

Error codes?

 

Have you tested your alternator for excessive AC noise?

 

After your sure the alternator is good and clean power I suggest doing the W-T ground mod.

 

No error codes haven’t tested anything yet wanted to go toward the right detection before jumping into something different 

Being AC noise will foul anything with a hall effect sensor like crank sensor or axle speed sensor I typically want to be sure the alternator isn't the cause first. 

Ok so I will check the alternator tomorrow, but if it’s not that then where to look or what to do?? 

Typically if there is any AC noise it will do weird stuff about 80% of the time its alternator related. The other 20% could be bad crank/cam sensor. Wiring issues. Bad grounds. Possibly cluster error.

Is it just on the dash or is the engine actually goes up and down in RPM, almost sounds like apps problem

But none the less check AC noise and do ground mod

The engine cuts out and drops speed but then comes right back 

 

1 hour ago, Dieselsmoke24v said:

The engine cuts out and drops speed but then comes right back 

 

 

Still pointing to AC noise issue common to see on a manual transmission truck. Like on my truck if fouls the tach signal and the ECM sees the AC noise for a moment the revs up past what I'm commanding for speed the AC noise frequency shifts and then the throttle cuts even though my foot hasn't moved nor has the TPS signal changed. But the RPM signal on the OBDII port is all over the map up and down. 

Mines automatic, where would the noice come from? Everyone’s pointing to the alternator I haven’t checked it yet because of work called me in on a emergency 

 

1 minute ago, Dieselsmoke24v said:

Mines automatic, where would the noice come from? Everyone’s pointing to the alternator I haven’t checked it yet because of work called me in on a emergency 

 

It originates from the alternator.

1 minute ago, dripley said:

It originates from the alternator.

Ok I’ll have to check that when I get home an see 

5 hours ago, Dieselsmoke24v said:

where would the noice come from?

 

Maybe I'm the only one interpretting this in this way but this isnt an actual noise you can hear its electronic noise. Just making sure we're all on the same page and if you already knew that then forget i said anything

It js definitely not a noise you can hear. You have test for it with a volt meter that reads mili volts. Mike posted a link to the test in the the 2nd post that describes the process quite well. It is easy to do with the right meter.

9 minutes ago, dripley said:

It js definitely not a noise you can hear. You have test for it with a volt meter that reads mili volts. Mike posted a link to the test in the the 2nd post that describes the process quite well. It is easy to do with the right meter.

 

I knew that i was just saying something for the OP's sake. Im also dealing with the dreaded AC noise right now I just had to make a 1000 mile road trip and i swear i felt every single AC ripple in the throttle it got so bad.. Diodes are on the way now lol

3 hours ago, 2000Ram2500 said:

 

I knew that i was just saying something for the OP's sake. Im also dealing with the dreaded AC noise right now I just had to make a 1000 mile road trip and i swear i felt every single AC ripple in the throttle it got so bad.. Diodes are on the way now lol

Was backing up what you said. All is good.

On 10/1/2018 at 9:39 AM, Dieselsmoke24v said:

Ok I’ll have to check that when I get home an see 

 

Any updates?

Hey everyone after a few late nights an loosing some sleep found it was the throttle positioning sensor was off, local shop was about to reset it gonna drive it for a while an see if it does it again, 

12 minutes ago, Dieselsmoke24v said:

it was the throttle positioning sensor was off

 

What do you mean off? 

 

Disconnected?

 

 

Voltage wise? If voltage wise do NOT reset the voltage or attempt to adjust the sensor!

 

 

He said they hooked it all up to a computer checked all the voltage everything was reading good maybe it was just the throttle position I can’t remember now little worried now, an they already closed I just got the truck back today 

 

Truck isles great runs down the road at 55 no issues got it up to 80 no problems shifts smooth, i can’t remember 100 persent what he said I do remember him saying throttle positioning, not sure what to look for an see what’s going on if he did reset it